Winter may not officially start until December 21, when Earth's northern hemisphere is tilted farthest away from the Sun. But meteorological winter arrived December 1 so we thought it would be a great time to discuss winter temperature trends.

Over the past 40 years or so, winters have gotten gradually warmer. From 1970-2012, winters in the continental United States have warmed up by 0.61° per decade on average.

That’s just an average, though. California and Nevada have only warmed at a rate of 0.17° per decade over that time (slowest winter warming region in the country), and the Southeast has gone up just 0.29° per decade. A couple of places—northeastern Nevada and south-central Wyoming—have actually cooled down during that time.

However, the winter warming trends for both the Upper Midwest and the Northeast have been higher than the national average. The Upper Midwest is warming the fastest of any region at 1.12° per decade and the Northeast comes in second at .78° per decade. The Ohio Valley rounds out the top three, warming at .66° per decade.

But that’s no surprise. Even in a world that’s warming overall, there will be regional variations. The upward temperature trend is consistent with what you’d expect to happen as heat-trapping greenhouse gases like carbon dioxide continue to build up in the atmosphere.

The Atlantic hurricane season ended on November 30. This season was the least active since 1982 and the sixth-quietest since 1950. We've included a graphic in this alert showing the number of storms in 2013 compared to the long-term average and the NOAA's forecast at the start of the season.